Wave-signal translating system



1940' i v H. M- LEWis 2,217,957 WAVE-SIGNAL TRANSLfiTING 4 Filed May 26,1 39 FIG. I.

INVENTOR H OLD M. LEWIS ATTORNEY Patented Oct.15,1940 V q I I I Y UNITED"STATES, PATENT. OFF-ICE] f 22,217,957. f Q a wAvE-smNAL 'rnANsLA'rmGSYSTEM H Harold M. Lewis, Great-Neck;N.lY., assignor-to A t 7HazeltineCox-poration', a corporation ofDela-- i ware 1 W V.

a Application May 26, 1939, SerialNo 275,781

10 Claims. 101. 118;)

This invention relates to wave-signal -transand itsscope'wjl be pointedout in the appended" lating systems. ,The invention is especiallyconclaims, v v cerned with signal-translating"systems of the 'Inthe-accompanying drawing,Fig.'1 is acirtype adapted to effectpredetermined time delay cuit'diagram; of anrelectric signal-translatingsys a in the translation of signals. tem embodyingthe present invention:while Fig; Various systems have heretofore been devised 2 is a. group ofcurvesillustratingthe waveforms;

for the purpose of effecting timedelays in the of-wavesappeanng atvarious. points in thesystranslation of wave signals. Ordinarily, thesetern ofzFig. 1 to aid in the understandingfof .the systems havecomprised networks or transmission invention I V 1 a lines having inputvterminals to which the sig-' Referring now more particularly to Fig;1Qqf1 Q, nals are appliedand output terminals at their the. drawing,there is illustrated a wavesigna'l remote ends at which the delayedsignals appear. translating system embodying, the present in;- 1 Inorder to obtain time delays of appreciable ventionand comprising aninput circuit includ-I magnitude, it has been necessary to providerelaing a resistor, in connected by way of a coupling tively longtransmission lines, either actual or condenser ll across a wave-signalsource indi artificial, embodying a large amount of relatively cated atS. Connected tothe input circuit in, II expensive physical apparatus,the amount of apis a first signal-translating channel comprisingaparatus required being substantially directly provacuum, tube. I3 havingits input electrodes con-9' portional'to the amount of timedelayrequired. pled to the input circuit I0, ll byway of asuit It is anobject of the present invention, thereable coupling condenser l4 andleak resistor l5.' fore, to provide an improved wave-signal trans- Asecond signal-translating channel is'also cou- Y lating system adaptedto provide apredetermined pled to the-input circuit and preferablycomprises time delay in the translation of a wave signal apolarity-reversing vacuum tube l6 having its and embodying a-relativelysmall amount of sphyscontrol grid connected to, a suitable tap 10a .onical apparatus;v w the resistor l0;.and having a load resistor I] in 2It is a further object of the invention to proits anode circuit.A-second vacuum tube'l8 is g I vide a system of the type described,characterincluded in the-second signal-translating chan ized bysimplicity of construction, efiiciency in nei with its input electrodesconnected across load operation, and adjustability for efiecting variousresistor illsbyway of suitable coupling condenser o controlsof thetranslated signal. and leak resistor 20. Thetubes l3 and I8, are 39 Inaccordance with thepresent invention, there connected in parallel to acommon outputcircuit is provided a wave-signal translating system cominludin a S e e i t r 2| and inductance 2- prising an input circuit towhich is coupleda re,- Preferably .the tub s and fa e a l o fi rfleeting delay network, preferably a dead-end filconventional pentodetype havingsuitable potenter network,'adapted.to reflect the signal witha tials applied totheir screens from sources indipredetermined timedelay. An output circuit catedfil'l In ac Ofthe O S dat is coupled tothe input circuit for translating the Ode cum-fits of these P F aSuitable bias 913 delayed signal and the input and output circuits Suchas a battery 1S 'mcluded- .Opemtmg are also coupled by additional meansfor neutral- .7 a I d a d and I8 from a-suitable,source 1nd1cated'at +340 izmg or substantially suppressing the un el ye by ay of me loadresistdr. H and du n 22 signal. The latter means preferably comprise I gand tothe-tube l6 b wa of the load resistor l1. means for reversing thepolarity of the undelayed For the purpose 3} efizctmg a predetermined jand m{ mm'the P delay in the translation ofthe wave signal applied withthe undelayed signal of opposite polarity. 'to thevinput Qircuit In forthe systemfthemis In a preferred embodiment of the invention, the p i{reflecting delay t rkyi c t remote end of the delay network isterminated mn t g'4 g r 24 omp a in an adjustable p d a means j Plow-pass filter of the dead-end type, including i e for adjusting s p nt r input terminals 25 which are connectedacross tentials are applied tothe anodes of thetubes l3 7 adjust the polarity an amplitude of thereflected the load resistor H by way of a suitabiecoupling 50 Wave- I lcondenser Fla, and an input terminating resistor For a betterunderstandingof the invention, to- 2B. The filter 24 as coupled to theinputtermigether with other and further objects thereof, nals 25comprises an m-derived half-section conreference is had toth'e followingdescription taken sisting of a shunt arm comprisinga series-coninconnection with the a o p i draw g nected inductance zeand condenser 28andase- 6 .7

ries arm comprising an inductance 21, coupled to a series of constant-kwhole-sections individually comprising full-series inductance arms 30and full-shunt condenser arms 3| and terminated in a mid-seriesinductance arm 32. Across the remote terminals of the filter there isconnected an adjustable terminating impedance, for example, a resistor33, the value of which may be varied over a wide range of values.

The operation of the system oi'the present invention may best beexplained with reference to the curves of Fig. 2. While the system isadapted for translation of a signal of anywave .i'orm or frequency, forthe purpose of'clarity, the

translation of a periodic rectangular-pulse signal is assumed by way ofexample. Curve A of Fig. 2 illustrates the appearance of such a wave asit may be supplied from the source S and impressed upon the inputcircuit I0, ll of the system. This wave is translated by the firstchannel of the system by way of the tube l3 with a reversal in itspolarity so that its wave form,:as repeated by this tube, is asillustrated bycurve B. The wave is further translated by the sec'- ondchannel of the system by way of the tubes l6 and I8, each of whicheffects a reversal in the polarity thereof, so that the signal-inputwave as repeated by tube I 3 has its original. polarity, as illustratedby curve A, opposite to that which it has as repeated by the tube I 3.By properly proportioning the gain of the tubes It, IS, and I8, andadjusting the signal input to tube It by tap Illa, these two waves'maybe made identical in amplitude but opposite in pop larity and, beingcombined in the additive common output circuit, they neutralize orcancel one another. The undelayed wave is thus substantially suppressedand does not appear across the output load circuit 2|, 22. The signalrepeated by the tube It is also impressed upon the input terminals 25 ofthe delay network 24 by way ofthe load-resistor i1 and condenser Ila.The delay network 24 comprises a two-terminal filter network and, withthe value of the terminating resistor" properlyadiusted, for example, toan extremely high value so that its remote terminals are open-circuited,the wave impressed on its input circuit is. translated to the remoteterminals and then reflected, back, with its original polarity, totheinput terminals 25 where it appears as illustrated by curve C of Fig.2. The reversal in polarity of wave C with respect tothe wave A is dueto the tube 13, the time delay indicated at D being effected by thenetwork. The time delay in the passage of the signal from its inputterminals 25 to its remote end need be but one-half of the desiredtlmedelay, since the signal is also delayed in its reflected passageback to the input terminals. Hence, only one-half of the physicalapparatus which would ordinarily be required to obtain the desired delayis utilized by the system c! the present invention. The resistor 23terminates the filter in its image impedance, so that there isno furtherreflection of the echo orreflected wave. The reflected waveof thenetwork 24 is impressed upon the input electrodes ofthe tube l8 and .isrepeated in the output circuit of this tube and a voltage representingthe delayed signal appears across the load circuit elements 2|, 22 freefrom the undelayed signal which is suppressed in this load circuit asdescribed above. By adjustment of the terminatingresistor 33 so that itsvalue is approximately zero, the filter is effectively short-circuitedat its remote end and, under this condition, the reflected wave is ofopposite polarity to that of the wave impressed on its input terminals.At an intermediate value or the resistor 33 corresponding to the imageimpedance of the fllter, there is no reflection 5 from the remote end,that is to say, the amplitude of the reflected wave is then zero.Adjustment of the resistor 33 thus affords a convenient conmi ofiboththe amplitude and polarity of the refleotedi delayed wave which istranslated by 10 the system,

While there has been described what is at present considered to be thepreferred embodiment of this invention, it will be obvious to thoseskilled in the art that various changes and modil5 ficatlons may be madetherein without departing from the invention. and it is, therefore,aimed in the appended claims to cover all such changes and modifications,as fall within the true spirit and scope of the invention. 20

What is claimed is 1.,A wave-signal translating system comprising aninput circuit adapted to have a wave signal impressed thereon, areflecting delay network coupled to said input-circuit, an outputcircuit 25 coupled to said n'etwork, for translating said delayedsignal, and additional means coupling said input and outputcircui'ts torneutralizing the undelayed signal in said output circuit.

2,.A wave-signal translating system compris- 30 ing an input circuitadapted to have a wave signal impressed thereon, a reflecting delaynetwork having input terminals coupled to said input circuitQan outputcircuit coupled to said terminals for translating said delayed signal,and ad- 35 ditional means coupling said input and output circuits forneutralizing the 'undelayed signal in said output circuit. 1

3. A wave-signal translating system comprising an input circuit adaptedto have a wave 813- O nal impressed thereon, a, reflecting delay networkhaving input terminals coupled to said input circuit, an output circuitcoupled to said terminals for translating the delayed signal andincidentally translating the undelayed signal, and additional meanscoupling saidinput and output circuits for translating said undelayedsignal therebetween with a polarity opposite to said incidentallytranslated undelayed signal, whereby said undelayed signal issubstantially suppressed 50 translating channel coupling said input andoutput circuits for translating said signal to said output circuit withequal amplitude and opposite polarity, whereby the undelayed signal issubstantially suppressed in said output circuit. and a reflecting delaynetwork having input terminals coupled to one of said channels andadapted to reflect said signal with a predeterminedtime de- 05 lay. i

5. A wave-signal translating system comprising an input circuit adaptedto have a wave impressed thereon, an output circuit, a firstsignaltranslating channel coupling said input and out- 7 put circuitsand including an odd number of vacuum-tube repeaters for translatingsaid signal to said output circuit with one polarity, a secondsignal-translating channel coupling said input and output circuits andincluding an even numl5 ber of vacuum-tube repeaters for translatingsaid signal to said output circuit with equal ampli tude and oppositepolarity, whereby the undelayed signal is substantially suppressed insaid output circuit, and a reflecting delay network having inputterminals coupled to one of said channels and adapted to reflect saidsignal with a predetermined time delay.

6. A wave-signal translating system comprising an input circuit adaptedto have a wave signal'impressed thereon, a reflecting delay networkhaving input terminals coupled to said input circuit, an output circuitcoupled to said terminals for translating said delayed signal,additional means coupling said input and output circuits forneutralizing the undelayed signal in said output circuit, and means foradjusting said network to control the amplitude of the delayedtranslated signal.

- 7. A wave-signal translating system comprising an input circuitadaptedto have a wave signal impressed thereon, a reflecting delaynetwork having input terminals coupled to said input circuit, an outputcircuit coupled to said terminals for translating said delayed signal,additional means coupling said input and output circuits forneutralizing the undelayed signal in said output circuit, and means foradjusting said network to control the amplitude and polarity of thedelayed translated signal.

8. A wave-signal translating system comprising an input circuit adaptedto have a wave impressed thereon, a dead-end filter network having inputterminals coupled to said input circuit and adapted to reflect saidsignal with a predetermined time delay, an output circuit coupled tosaid terminals for translating the delayed signal,

and means connected between said input and output circuits forneutralizing thevundelayed signal in said output circuit.

9. A wave-signal translating system comprising an input circuit adaptedto have a wave impressed thereon, a dead-end filter network having itsinput terminals coupled to said input circuit and adapted to reflectsaid signal with a predetermined time delay, said network including anadjustable terminating impedance at its remote end, an output circuitcoupled to said network for translating the delayed signal, meansconnected between said input and output circuits for neutralizing theundelayed signal in said output circuit, whereby adjustment of saidimpedance is efiective to vary the amplitude and polarity oi thetranslated delayed signal.

10. A wave-signal translating system comprising an input circuit adaptedto have a wave impressed thereon, an output circuit, a firstsignaltranslating channel coupling said input and output circuits fortranslating said signal to said'output circuit with one polarity, asecond signaltranslating channel for translating said signal to saidoutput circuit with an opposite polarity,

whereby the undelayed signal is substantially suppressed in said outputcircuit, and a dead-end filter network including an adjustable terminating impedance at its remote end and having input terminals coupled toone of said channels for reflecting said signal with a predeterminedtime delay, whereby adjustment of said impedance is efiective to varythe amplitude and polarityof the translated delayed signal.

- HAROLD M. LEWIS.

